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This is a paid asset, but now you can download MeshKit – Mesh Decimation, Separation, Combining and Editing Tools Free.
MeshKit – Mesh Decimation, Separation, Combining and Editing Tools v2.1.1 (Latest version)
Supports Unity 2017.x to 2020.x!
MeshKit is an integrated plugin for editing and optimising meshes. MeshKit includes an in-depth asset management system which cleans your unused assets and helps protect your meshes from accidental deletion – a common scenario for combining meshes or using prefabs with a shared mesh across different scenes.
Mesh Kit offers some handy tools to Separate meshes as well as to flip, make them double-sided, or to dynamically rebuild them with or without tangents and normals on the fly – all without affecting the original mesh.
MeshKit also excels at combining 3D assets that were not even designed for games, offering a dedicated approach for dealing with Submeshes using powerful separation tools. This streamlines your game, significantly reduces draw calls and reduces overhead!
That’s not all, MeshKit includes a powerful decimator tool which can reduce the triangles of complex meshes as well as an Automatic LOD tool that can dynamically create a decimated LOD Group with a single click! As objects move away from the camera, their lower poly versions will be used which boosts performance!
MeshKit offers its mesh functionality via Editor Inspectors, Runtime Components and a fully accessible API.
– Reduce mesh triangles with a Powerful Decimator!
– One-click Auto LOD tool!
– Separate and combine Meshes!
– Combines meshes with over 64k vertices
– Set max number of vertices per object.
– Invert meshes.
– Make meshes double-sided.
– Strip unneeded vertices and extras from meshes.
– Remove / add tangents and normals.
– Recreate Lightmap UVs (Editor Only).
– MeshKit Editor Tools.
– Runtime components.
– Powerful and easy to use API.
– Compatible with Unity 2017.x, to 2020.x!
– In-depth asset management to delete unused assets and automatically handle organising the meshes of prefabs and local scene meshes.
> MeshKit PDF Manual
> MeshKit Unity Forum